Chapter 124. Sexually Transmitted Infections: Overview and Clinical Approach (Part 4) pps

Chapter 124. Sexually Transmitted Infections:
Overview and Clinical Approach
(Part 4)

Risk assessment is followed by clinical assessment (elicitation of
information on specific current symptoms and signs of STDs). Confirmatory
diagnostic tests (for persons with symptoms or signs) or screening tests (for those
without symptoms or signs) may involve microscopic examination, culture,
antigen detection tests, genetic probe or amplification tests, or serology. Initial
syndrome-based treatment should cover the most likely causes. For certain
syndromes, results of rapid tests can narrow the spectrum of this initial therapy
(e.g., wet mount of vaginal fluid for women with vaginal discharge, Gram's stain
of urethral discharge for men with urethral discharge, rapid plasma reagin test for
genital ulcer). After the institution of treatment, STD management proceeds to the
"4 C's" of prevention and control: contact tracing (see "Prevention and Control of
STIs," below), ensuring compliance with therapy, and counseling on risk
reduction, including condom promotion and provision.

Urethritis in Men
Urethritis in men produces urethral discharge, dysuria, or both, usually
without frequency of urination. Causes include Neisseria gonorrhoeae, C.
trachomatis, Mycoplasma genitalium, Ureaplasma urealyticum, Trichomonas
vaginalis, HSV, and perhaps adenovirus.
Until recently, C. trachomatis caused ~30–40% of cases of nongonococcal
urethritis (NGU); however, the proportion of cases due to this organism may have
declined in some populations served by effective chlamydial-control programs,
and older men with urethritis appear less likely to have chlamydial infection. HSV
and T. vaginalis each cause a small proportion of NGU cases in the United States.
Recently, multiple studies have consistently implicated M. genitalium as a
probable cause of many Chlamydia-negative cases. Fewer studies than in the past
have implicated Ureaplasma; the ureaplasmas have been differentiated into U.

urealyticum and U. parvum, and a few studies suggest that U. urealyticum—but
not U. parvum—is associated with NGU. Coliform bacteria can cause urethritis in
men who practice insertive anal intercourse. The initial diagnosis of urethritis in
men currently includes specific tests only for N. gonorrhoeae and C. trachomatis.
The following summarizes the approach to the patient with suspected urethritis:
1. Establish the presence of urethritis. If proximal-to-distal
"milking" of the urethra does not express a purulent or mucopurulent
discharge, even after the patient has not voided for several hours (or
preferably overnight), a Gram's-stained smear of overt discharge or of an
anterior urethral specimen obtained by passage of a small urethrogenital
swab 2–3 cm into the urethra usually reveals ≥5 neutrophils per 1000x field
in areas containing cells; in gonococcal infection, such a smear usually
reveals gram-negative intracellular diplococci as well. Alternatively, the
centrifuged sediment of the first 20–30 mL of voided urine—ideally
collected as the first morning specimen—can be examined for
inflammatory cells, either by microscopy showing ≥10 leukocytes per high-
power field or by the leukocyte esterase test. Patients with symptoms who
lack objective evidence of urethritis may have functional rather than
organic problems and generally do not benefit from repeated courses of
antibiotics.

2. Evaluate for complications or alternative diagnoses. A brief
history and examination will exclude epididymitis and systemic
complications, such as disseminated gonococcal infection (DGI) and
Reiter's syndrome. Although digital examination of the prostate gland
seldom contributes to the evaluation of sexually active young men with
urethritis, men with dysuria who lack evidence of urethritis as well as
sexually inactive men with urethritis should undergo prostate palpation,
urinalysis, and urine culture to exclude bacterial prostatitis and cystitis.

3. Evaluate for gonococcal and chlamydial infection. An
absence of typical gram-negative diplococci on Gram's-stained smear of
urethral exudate containing inflammatory cells warrants a preliminary
diagnosis of NGU and should lead to testing of the urethral specimen for C.
trachomatis. However, an increasing proportion of men with symptoms
and/or signs of urethritis are simultaneously assessed for infection with N.
gonorrhoeae and C. trachomatis by "multiplex" nucleic acid amplification
tests (NAATs) of early-morning first-voided urine. Culture or NAAT for N.
gonorrhoeae may be positive when Gram's staining is negative; certain
strains of N. gonorrhoeae can result in negative urethral Gram's stains in up
to 30% of cases of urethritis. Results of tests for gonococcal and chlamydial
infection predict the patient's prognosis (with greater risk for recurrent
NGU if neither chlamydiae nor gonococci are found than if either is
detected) and can guide both the counseling given to the patient and the
management of the patient's sexual partner(s).